xref: /linux/fs/nfs/client.c (revision 5c35a02c545a7bbe77f3a1ae337d9e29beed079b)
1 /* client.c: NFS client sharing and management code
2  *
3  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/sched.h>
16 #include <linux/time.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/stat.h>
21 #include <linux/errno.h>
22 #include <linux/unistd.h>
23 #include <linux/sunrpc/addr.h>
24 #include <linux/sunrpc/clnt.h>
25 #include <linux/sunrpc/stats.h>
26 #include <linux/sunrpc/metrics.h>
27 #include <linux/sunrpc/xprtsock.h>
28 #include <linux/sunrpc/xprtrdma.h>
29 #include <linux/nfs_fs.h>
30 #include <linux/nfs_mount.h>
31 #include <linux/nfs4_mount.h>
32 #include <linux/lockd/bind.h>
33 #include <linux/seq_file.h>
34 #include <linux/mount.h>
35 #include <linux/vfs.h>
36 #include <linux/inet.h>
37 #include <linux/in6.h>
38 #include <linux/slab.h>
39 #include <linux/idr.h>
40 #include <net/ipv6.h>
41 #include <linux/nfs_xdr.h>
42 #include <linux/sunrpc/bc_xprt.h>
43 #include <linux/nsproxy.h>
44 #include <linux/pid_namespace.h>
45 
46 
47 #include "nfs4_fs.h"
48 #include "callback.h"
49 #include "delegation.h"
50 #include "iostat.h"
51 #include "internal.h"
52 #include "fscache.h"
53 #include "pnfs.h"
54 #include "nfs.h"
55 #include "netns.h"
56 
57 #define NFSDBG_FACILITY		NFSDBG_CLIENT
58 
59 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
60 static DEFINE_SPINLOCK(nfs_version_lock);
61 static DEFINE_MUTEX(nfs_version_mutex);
62 static LIST_HEAD(nfs_versions);
63 
64 /*
65  * RPC cruft for NFS
66  */
67 static const struct rpc_version *nfs_version[5] = {
68 	[2] = NULL,
69 	[3] = NULL,
70 	[4] = NULL,
71 };
72 
73 const struct rpc_program nfs_program = {
74 	.name			= "nfs",
75 	.number			= NFS_PROGRAM,
76 	.nrvers			= ARRAY_SIZE(nfs_version),
77 	.version		= nfs_version,
78 	.stats			= &nfs_rpcstat,
79 	.pipe_dir_name		= NFS_PIPE_DIRNAME,
80 };
81 
82 struct rpc_stat nfs_rpcstat = {
83 	.program		= &nfs_program
84 };
85 
86 static struct nfs_subversion *find_nfs_version(unsigned int version)
87 {
88 	struct nfs_subversion *nfs;
89 	spin_lock(&nfs_version_lock);
90 
91 	list_for_each_entry(nfs, &nfs_versions, list) {
92 		if (nfs->rpc_ops->version == version) {
93 			spin_unlock(&nfs_version_lock);
94 			return nfs;
95 		}
96 	}
97 
98 	spin_unlock(&nfs_version_lock);
99 	return ERR_PTR(-EPROTONOSUPPORT);
100 }
101 
102 struct nfs_subversion *get_nfs_version(unsigned int version)
103 {
104 	struct nfs_subversion *nfs = find_nfs_version(version);
105 
106 	if (IS_ERR(nfs)) {
107 		mutex_lock(&nfs_version_mutex);
108 		request_module("nfsv%d", version);
109 		nfs = find_nfs_version(version);
110 		mutex_unlock(&nfs_version_mutex);
111 	}
112 
113 	if (!IS_ERR(nfs) && !try_module_get(nfs->owner))
114 		return ERR_PTR(-EAGAIN);
115 	return nfs;
116 }
117 
118 void put_nfs_version(struct nfs_subversion *nfs)
119 {
120 	module_put(nfs->owner);
121 }
122 
123 void register_nfs_version(struct nfs_subversion *nfs)
124 {
125 	spin_lock(&nfs_version_lock);
126 
127 	list_add(&nfs->list, &nfs_versions);
128 	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
129 
130 	spin_unlock(&nfs_version_lock);
131 }
132 EXPORT_SYMBOL_GPL(register_nfs_version);
133 
134 void unregister_nfs_version(struct nfs_subversion *nfs)
135 {
136 	spin_lock(&nfs_version_lock);
137 
138 	nfs_version[nfs->rpc_ops->version] = NULL;
139 	list_del(&nfs->list);
140 
141 	spin_unlock(&nfs_version_lock);
142 }
143 EXPORT_SYMBOL_GPL(unregister_nfs_version);
144 
145 /*
146  * Allocate a shared client record
147  *
148  * Since these are allocated/deallocated very rarely, we don't
149  * bother putting them in a slab cache...
150  */
151 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
152 {
153 	struct nfs_client *clp;
154 	struct rpc_cred *cred;
155 	int err = -ENOMEM;
156 
157 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
158 		goto error_0;
159 
160 	clp->cl_nfs_mod = cl_init->nfs_mod;
161 	if (!try_module_get(clp->cl_nfs_mod->owner))
162 		goto error_dealloc;
163 
164 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
165 
166 	refcount_set(&clp->cl_count, 1);
167 	clp->cl_cons_state = NFS_CS_INITING;
168 
169 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
170 	clp->cl_addrlen = cl_init->addrlen;
171 
172 	if (cl_init->hostname) {
173 		err = -ENOMEM;
174 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
175 		if (!clp->cl_hostname)
176 			goto error_cleanup;
177 	}
178 
179 	INIT_LIST_HEAD(&clp->cl_superblocks);
180 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
181 
182 	clp->cl_proto = cl_init->proto;
183 	clp->cl_net = get_net(cl_init->net);
184 
185 	cred = rpc_lookup_machine_cred("*");
186 	if (!IS_ERR(cred))
187 		clp->cl_machine_cred = cred;
188 	nfs_fscache_get_client_cookie(clp);
189 
190 	return clp;
191 
192 error_cleanup:
193 	put_nfs_version(clp->cl_nfs_mod);
194 error_dealloc:
195 	kfree(clp);
196 error_0:
197 	return ERR_PTR(err);
198 }
199 EXPORT_SYMBOL_GPL(nfs_alloc_client);
200 
201 #if IS_ENABLED(CONFIG_NFS_V4)
202 void nfs_cleanup_cb_ident_idr(struct net *net)
203 {
204 	struct nfs_net *nn = net_generic(net, nfs_net_id);
205 
206 	idr_destroy(&nn->cb_ident_idr);
207 }
208 
209 /* nfs_client_lock held */
210 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
211 {
212 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
213 
214 	if (clp->cl_cb_ident)
215 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
216 }
217 
218 static void pnfs_init_server(struct nfs_server *server)
219 {
220 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
221 }
222 
223 #else
224 void nfs_cleanup_cb_ident_idr(struct net *net)
225 {
226 }
227 
228 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
229 {
230 }
231 
232 static void pnfs_init_server(struct nfs_server *server)
233 {
234 }
235 
236 #endif /* CONFIG_NFS_V4 */
237 
238 /*
239  * Destroy a shared client record
240  */
241 void nfs_free_client(struct nfs_client *clp)
242 {
243 	nfs_fscache_release_client_cookie(clp);
244 
245 	/* -EIO all pending I/O */
246 	if (!IS_ERR(clp->cl_rpcclient))
247 		rpc_shutdown_client(clp->cl_rpcclient);
248 
249 	if (clp->cl_machine_cred != NULL)
250 		put_rpccred(clp->cl_machine_cred);
251 
252 	put_net(clp->cl_net);
253 	put_nfs_version(clp->cl_nfs_mod);
254 	kfree(clp->cl_hostname);
255 	kfree(clp->cl_acceptor);
256 	kfree(clp);
257 }
258 EXPORT_SYMBOL_GPL(nfs_free_client);
259 
260 /*
261  * Release a reference to a shared client record
262  */
263 void nfs_put_client(struct nfs_client *clp)
264 {
265 	struct nfs_net *nn;
266 
267 	if (!clp)
268 		return;
269 
270 	nn = net_generic(clp->cl_net, nfs_net_id);
271 
272 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
273 		list_del(&clp->cl_share_link);
274 		nfs_cb_idr_remove_locked(clp);
275 		spin_unlock(&nn->nfs_client_lock);
276 
277 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
278 
279 		clp->rpc_ops->free_client(clp);
280 	}
281 }
282 EXPORT_SYMBOL_GPL(nfs_put_client);
283 
284 /*
285  * Find an nfs_client on the list that matches the initialisation data
286  * that is supplied.
287  */
288 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
289 {
290 	struct nfs_client *clp;
291 	const struct sockaddr *sap = data->addr;
292 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
293 
294 again:
295 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
296 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
297 		/* Don't match clients that failed to initialise properly */
298 		if (clp->cl_cons_state < 0)
299 			continue;
300 
301 		/* If a client is still initializing then we need to wait */
302 		if (clp->cl_cons_state > NFS_CS_READY) {
303 			refcount_inc(&clp->cl_count);
304 			spin_unlock(&nn->nfs_client_lock);
305 			nfs_wait_client_init_complete(clp);
306 			nfs_put_client(clp);
307 			spin_lock(&nn->nfs_client_lock);
308 			goto again;
309 		}
310 
311 		/* Different NFS versions cannot share the same nfs_client */
312 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
313 			continue;
314 
315 		if (clp->cl_proto != data->proto)
316 			continue;
317 		/* Match nfsv4 minorversion */
318 		if (clp->cl_minorversion != data->minorversion)
319 			continue;
320 		/* Match the full socket address */
321 		if (!rpc_cmp_addr_port(sap, clap))
322 			/* Match all xprt_switch full socket addresses */
323 			if (IS_ERR(clp->cl_rpcclient) ||
324                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
325 							   sap))
326 				continue;
327 
328 		refcount_inc(&clp->cl_count);
329 		return clp;
330 	}
331 	return NULL;
332 }
333 
334 /*
335  * Return true if @clp is done initializing, false if still working on it.
336  *
337  * Use nfs_client_init_status to check if it was successful.
338  */
339 bool nfs_client_init_is_complete(const struct nfs_client *clp)
340 {
341 	return clp->cl_cons_state <= NFS_CS_READY;
342 }
343 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
344 
345 /*
346  * Return 0 if @clp was successfully initialized, -errno otherwise.
347  *
348  * This must be called *after* nfs_client_init_is_complete() returns true,
349  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
350  */
351 int nfs_client_init_status(const struct nfs_client *clp)
352 {
353 	/* called without checking nfs_client_init_is_complete */
354 	if (clp->cl_cons_state > NFS_CS_READY) {
355 		WARN_ON_ONCE(1);
356 		return -EINVAL;
357 	}
358 	return clp->cl_cons_state;
359 }
360 EXPORT_SYMBOL_GPL(nfs_client_init_status);
361 
362 int nfs_wait_client_init_complete(const struct nfs_client *clp)
363 {
364 	return wait_event_killable(nfs_client_active_wq,
365 			nfs_client_init_is_complete(clp));
366 }
367 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
368 
369 /*
370  * Found an existing client.  Make sure it's ready before returning.
371  */
372 static struct nfs_client *
373 nfs_found_client(const struct nfs_client_initdata *cl_init,
374 		 struct nfs_client *clp)
375 {
376 	int error;
377 
378 	error = nfs_wait_client_init_complete(clp);
379 	if (error < 0) {
380 		nfs_put_client(clp);
381 		return ERR_PTR(-ERESTARTSYS);
382 	}
383 
384 	if (clp->cl_cons_state < NFS_CS_READY) {
385 		error = clp->cl_cons_state;
386 		nfs_put_client(clp);
387 		return ERR_PTR(error);
388 	}
389 
390 	smp_rmb();
391 	return clp;
392 }
393 
394 /*
395  * Look up a client by IP address and protocol version
396  * - creates a new record if one doesn't yet exist
397  */
398 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
399 {
400 	struct nfs_client *clp, *new = NULL;
401 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
402 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
403 
404 	if (cl_init->hostname == NULL) {
405 		WARN_ON(1);
406 		return NULL;
407 	}
408 
409 	/* see if the client already exists */
410 	do {
411 		spin_lock(&nn->nfs_client_lock);
412 
413 		clp = nfs_match_client(cl_init);
414 		if (clp) {
415 			spin_unlock(&nn->nfs_client_lock);
416 			if (new)
417 				new->rpc_ops->free_client(new);
418 			return nfs_found_client(cl_init, clp);
419 		}
420 		if (new) {
421 			list_add_tail(&new->cl_share_link,
422 					&nn->nfs_client_list);
423 			spin_unlock(&nn->nfs_client_lock);
424 			new->cl_flags = cl_init->init_flags;
425 			return rpc_ops->init_client(new, cl_init);
426 		}
427 
428 		spin_unlock(&nn->nfs_client_lock);
429 
430 		new = rpc_ops->alloc_client(cl_init);
431 	} while (!IS_ERR(new));
432 
433 	return new;
434 }
435 EXPORT_SYMBOL_GPL(nfs_get_client);
436 
437 /*
438  * Mark a server as ready or failed
439  */
440 void nfs_mark_client_ready(struct nfs_client *clp, int state)
441 {
442 	smp_wmb();
443 	clp->cl_cons_state = state;
444 	wake_up_all(&nfs_client_active_wq);
445 }
446 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
447 
448 /*
449  * Initialise the timeout values for a connection
450  */
451 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
452 				    int timeo, int retrans)
453 {
454 	to->to_initval = timeo * HZ / 10;
455 	to->to_retries = retrans;
456 
457 	switch (proto) {
458 	case XPRT_TRANSPORT_TCP:
459 	case XPRT_TRANSPORT_RDMA:
460 		if (retrans == NFS_UNSPEC_RETRANS)
461 			to->to_retries = NFS_DEF_TCP_RETRANS;
462 		if (timeo == NFS_UNSPEC_TIMEO || to->to_retries == 0)
463 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
464 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
465 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
466 		to->to_increment = to->to_initval;
467 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
468 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
469 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
470 		if (to->to_maxval < to->to_initval)
471 			to->to_maxval = to->to_initval;
472 		to->to_exponential = 0;
473 		break;
474 	case XPRT_TRANSPORT_UDP:
475 		if (retrans == NFS_UNSPEC_RETRANS)
476 			to->to_retries = NFS_DEF_UDP_RETRANS;
477 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
478 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
479 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
480 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
481 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
482 		to->to_exponential = 1;
483 		break;
484 	default:
485 		BUG();
486 	}
487 }
488 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
489 
490 /*
491  * Create an RPC client handle
492  */
493 int nfs_create_rpc_client(struct nfs_client *clp,
494 			  const struct nfs_client_initdata *cl_init,
495 			  rpc_authflavor_t flavor)
496 {
497 	struct rpc_clnt		*clnt = NULL;
498 	struct rpc_create_args args = {
499 		.net		= clp->cl_net,
500 		.protocol	= clp->cl_proto,
501 		.address	= (struct sockaddr *)&clp->cl_addr,
502 		.addrsize	= clp->cl_addrlen,
503 		.timeout	= cl_init->timeparms,
504 		.servername	= clp->cl_hostname,
505 		.nodename	= cl_init->nodename,
506 		.program	= &nfs_program,
507 		.version	= clp->rpc_ops->version,
508 		.authflavor	= flavor,
509 	};
510 
511 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
512 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
513 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
514 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
515 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
516 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
517 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
518 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
519 
520 	if (!IS_ERR(clp->cl_rpcclient))
521 		return 0;
522 
523 	clnt = rpc_create(&args);
524 	if (IS_ERR(clnt)) {
525 		dprintk("%s: cannot create RPC client. Error = %ld\n",
526 				__func__, PTR_ERR(clnt));
527 		return PTR_ERR(clnt);
528 	}
529 
530 	clp->cl_rpcclient = clnt;
531 	return 0;
532 }
533 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
534 
535 /*
536  * Version 2 or 3 client destruction
537  */
538 static void nfs_destroy_server(struct nfs_server *server)
539 {
540 	if (server->nlm_host)
541 		nlmclnt_done(server->nlm_host);
542 }
543 
544 /*
545  * Version 2 or 3 lockd setup
546  */
547 static int nfs_start_lockd(struct nfs_server *server)
548 {
549 	struct nlm_host *host;
550 	struct nfs_client *clp = server->nfs_client;
551 	struct nlmclnt_initdata nlm_init = {
552 		.hostname	= clp->cl_hostname,
553 		.address	= (struct sockaddr *)&clp->cl_addr,
554 		.addrlen	= clp->cl_addrlen,
555 		.nfs_version	= clp->rpc_ops->version,
556 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
557 					1 : 0,
558 		.net		= clp->cl_net,
559 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
560 	};
561 
562 	if (nlm_init.nfs_version > 3)
563 		return 0;
564 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
565 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
566 		return 0;
567 
568 	switch (clp->cl_proto) {
569 		default:
570 			nlm_init.protocol = IPPROTO_TCP;
571 			break;
572 		case XPRT_TRANSPORT_UDP:
573 			nlm_init.protocol = IPPROTO_UDP;
574 	}
575 
576 	host = nlmclnt_init(&nlm_init);
577 	if (IS_ERR(host))
578 		return PTR_ERR(host);
579 
580 	server->nlm_host = host;
581 	server->destroy = nfs_destroy_server;
582 	return 0;
583 }
584 
585 /*
586  * Create a general RPC client
587  */
588 int nfs_init_server_rpcclient(struct nfs_server *server,
589 		const struct rpc_timeout *timeo,
590 		rpc_authflavor_t pseudoflavour)
591 {
592 	struct nfs_client *clp = server->nfs_client;
593 
594 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
595 							pseudoflavour);
596 	if (IS_ERR(server->client)) {
597 		dprintk("%s: couldn't create rpc_client!\n", __func__);
598 		return PTR_ERR(server->client);
599 	}
600 
601 	memcpy(&server->client->cl_timeout_default,
602 			timeo,
603 			sizeof(server->client->cl_timeout_default));
604 	server->client->cl_timeout = &server->client->cl_timeout_default;
605 	server->client->cl_softrtry = 0;
606 	if (server->flags & NFS_MOUNT_SOFT)
607 		server->client->cl_softrtry = 1;
608 
609 	return 0;
610 }
611 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
612 
613 /**
614  * nfs_init_client - Initialise an NFS2 or NFS3 client
615  *
616  * @clp: nfs_client to initialise
617  * @cl_init: Initialisation parameters
618  *
619  * Returns pointer to an NFS client, or an ERR_PTR value.
620  */
621 struct nfs_client *nfs_init_client(struct nfs_client *clp,
622 				   const struct nfs_client_initdata *cl_init)
623 {
624 	int error;
625 
626 	/* the client is already initialised */
627 	if (clp->cl_cons_state == NFS_CS_READY)
628 		return clp;
629 
630 	/*
631 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
632 	 * - RFC 2623, sec 2.3.2
633 	 */
634 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
635 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
636 	if (error < 0) {
637 		nfs_put_client(clp);
638 		clp = ERR_PTR(error);
639 	}
640 	return clp;
641 }
642 EXPORT_SYMBOL_GPL(nfs_init_client);
643 
644 /*
645  * Create a version 2 or 3 client
646  */
647 static int nfs_init_server(struct nfs_server *server,
648 			   const struct nfs_parsed_mount_data *data,
649 			   struct nfs_subversion *nfs_mod)
650 {
651 	struct rpc_timeout timeparms;
652 	struct nfs_client_initdata cl_init = {
653 		.hostname = data->nfs_server.hostname,
654 		.addr = (const struct sockaddr *)&data->nfs_server.address,
655 		.addrlen = data->nfs_server.addrlen,
656 		.nfs_mod = nfs_mod,
657 		.proto = data->nfs_server.protocol,
658 		.net = data->net,
659 		.timeparms = &timeparms,
660 	};
661 	struct nfs_client *clp;
662 	int error;
663 
664 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
665 			data->timeo, data->retrans);
666 	if (data->flags & NFS_MOUNT_NORESVPORT)
667 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
668 
669 	/* Allocate or find a client reference we can use */
670 	clp = nfs_get_client(&cl_init);
671 	if (IS_ERR(clp))
672 		return PTR_ERR(clp);
673 
674 	server->nfs_client = clp;
675 
676 	/* Initialise the client representation from the mount data */
677 	server->flags = data->flags;
678 	server->options = data->options;
679 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
680 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
681 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
682 
683 	if (data->rsize)
684 		server->rsize = nfs_block_size(data->rsize, NULL);
685 	if (data->wsize)
686 		server->wsize = nfs_block_size(data->wsize, NULL);
687 
688 	server->acregmin = data->acregmin * HZ;
689 	server->acregmax = data->acregmax * HZ;
690 	server->acdirmin = data->acdirmin * HZ;
691 	server->acdirmax = data->acdirmax * HZ;
692 
693 	/* Start lockd here, before we might error out */
694 	error = nfs_start_lockd(server);
695 	if (error < 0)
696 		goto error;
697 
698 	server->port = data->nfs_server.port;
699 	server->auth_info = data->auth_info;
700 
701 	error = nfs_init_server_rpcclient(server, &timeparms,
702 					  data->selected_flavor);
703 	if (error < 0)
704 		goto error;
705 
706 	/* Preserve the values of mount_server-related mount options */
707 	if (data->mount_server.addrlen) {
708 		memcpy(&server->mountd_address, &data->mount_server.address,
709 			data->mount_server.addrlen);
710 		server->mountd_addrlen = data->mount_server.addrlen;
711 	}
712 	server->mountd_version = data->mount_server.version;
713 	server->mountd_port = data->mount_server.port;
714 	server->mountd_protocol = data->mount_server.protocol;
715 
716 	server->namelen  = data->namlen;
717 	return 0;
718 
719 error:
720 	server->nfs_client = NULL;
721 	nfs_put_client(clp);
722 	return error;
723 }
724 
725 /*
726  * Load up the server record from information gained in an fsinfo record
727  */
728 static void nfs_server_set_fsinfo(struct nfs_server *server,
729 				  struct nfs_fsinfo *fsinfo)
730 {
731 	unsigned long max_rpc_payload;
732 
733 	/* Work out a lot of parameters */
734 	if (server->rsize == 0)
735 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
736 	if (server->wsize == 0)
737 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
738 
739 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
740 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
741 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
742 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
743 
744 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
745 	if (server->rsize > max_rpc_payload)
746 		server->rsize = max_rpc_payload;
747 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
748 		server->rsize = NFS_MAX_FILE_IO_SIZE;
749 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
750 
751 	if (server->wsize > max_rpc_payload)
752 		server->wsize = max_rpc_payload;
753 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
754 		server->wsize = NFS_MAX_FILE_IO_SIZE;
755 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
756 
757 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
758 
759 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
760 	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
761 		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
762 	if (server->dtsize > server->rsize)
763 		server->dtsize = server->rsize;
764 
765 	if (server->flags & NFS_MOUNT_NOAC) {
766 		server->acregmin = server->acregmax = 0;
767 		server->acdirmin = server->acdirmax = 0;
768 	}
769 
770 	server->maxfilesize = fsinfo->maxfilesize;
771 
772 	server->time_delta = fsinfo->time_delta;
773 
774 	server->clone_blksize = fsinfo->clone_blksize;
775 	/* We're airborne Set socket buffersize */
776 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
777 }
778 
779 /*
780  * Probe filesystem information, including the FSID on v2/v3
781  */
782 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
783 {
784 	struct nfs_fsinfo fsinfo;
785 	struct nfs_client *clp = server->nfs_client;
786 	int error;
787 
788 	if (clp->rpc_ops->set_capabilities != NULL) {
789 		error = clp->rpc_ops->set_capabilities(server, mntfh);
790 		if (error < 0)
791 			return error;
792 	}
793 
794 	fsinfo.fattr = fattr;
795 	fsinfo.nlayouttypes = 0;
796 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
797 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
798 	if (error < 0)
799 		return error;
800 
801 	nfs_server_set_fsinfo(server, &fsinfo);
802 
803 	/* Get some general file system info */
804 	if (server->namelen == 0) {
805 		struct nfs_pathconf pathinfo;
806 
807 		pathinfo.fattr = fattr;
808 		nfs_fattr_init(fattr);
809 
810 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
811 			server->namelen = pathinfo.max_namelen;
812 	}
813 
814 	return 0;
815 }
816 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
817 
818 /*
819  * Copy useful information when duplicating a server record
820  */
821 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
822 {
823 	target->flags = source->flags;
824 	target->rsize = source->rsize;
825 	target->wsize = source->wsize;
826 	target->acregmin = source->acregmin;
827 	target->acregmax = source->acregmax;
828 	target->acdirmin = source->acdirmin;
829 	target->acdirmax = source->acdirmax;
830 	target->caps = source->caps;
831 	target->options = source->options;
832 	target->auth_info = source->auth_info;
833 	target->port = source->port;
834 }
835 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
836 
837 void nfs_server_insert_lists(struct nfs_server *server)
838 {
839 	struct nfs_client *clp = server->nfs_client;
840 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
841 
842 	spin_lock(&nn->nfs_client_lock);
843 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
844 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
845 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
846 	spin_unlock(&nn->nfs_client_lock);
847 
848 }
849 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
850 
851 void nfs_server_remove_lists(struct nfs_server *server)
852 {
853 	struct nfs_client *clp = server->nfs_client;
854 	struct nfs_net *nn;
855 
856 	if (clp == NULL)
857 		return;
858 	nn = net_generic(clp->cl_net, nfs_net_id);
859 	spin_lock(&nn->nfs_client_lock);
860 	list_del_rcu(&server->client_link);
861 	if (list_empty(&clp->cl_superblocks))
862 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
863 	list_del(&server->master_link);
864 	spin_unlock(&nn->nfs_client_lock);
865 
866 	synchronize_rcu();
867 }
868 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
869 
870 /*
871  * Allocate and initialise a server record
872  */
873 struct nfs_server *nfs_alloc_server(void)
874 {
875 	struct nfs_server *server;
876 
877 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
878 	if (!server)
879 		return NULL;
880 
881 	server->client = server->client_acl = ERR_PTR(-EINVAL);
882 
883 	/* Zero out the NFS state stuff */
884 	INIT_LIST_HEAD(&server->client_link);
885 	INIT_LIST_HEAD(&server->master_link);
886 	INIT_LIST_HEAD(&server->delegations);
887 	INIT_LIST_HEAD(&server->layouts);
888 	INIT_LIST_HEAD(&server->state_owners_lru);
889 
890 	atomic_set(&server->active, 0);
891 
892 	server->io_stats = nfs_alloc_iostats();
893 	if (!server->io_stats) {
894 		kfree(server);
895 		return NULL;
896 	}
897 
898 	ida_init(&server->openowner_id);
899 	ida_init(&server->lockowner_id);
900 	pnfs_init_server(server);
901 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
902 
903 	return server;
904 }
905 EXPORT_SYMBOL_GPL(nfs_alloc_server);
906 
907 /*
908  * Free up a server record
909  */
910 void nfs_free_server(struct nfs_server *server)
911 {
912 	nfs_server_remove_lists(server);
913 
914 	if (server->destroy != NULL)
915 		server->destroy(server);
916 
917 	if (!IS_ERR(server->client_acl))
918 		rpc_shutdown_client(server->client_acl);
919 	if (!IS_ERR(server->client))
920 		rpc_shutdown_client(server->client);
921 
922 	nfs_put_client(server->nfs_client);
923 
924 	ida_destroy(&server->lockowner_id);
925 	ida_destroy(&server->openowner_id);
926 	nfs_free_iostats(server->io_stats);
927 	kfree(server);
928 	nfs_release_automount_timer();
929 }
930 EXPORT_SYMBOL_GPL(nfs_free_server);
931 
932 /*
933  * Create a version 2 or 3 volume record
934  * - keyed on server and FSID
935  */
936 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
937 				     struct nfs_subversion *nfs_mod)
938 {
939 	struct nfs_server *server;
940 	struct nfs_fattr *fattr;
941 	int error;
942 
943 	server = nfs_alloc_server();
944 	if (!server)
945 		return ERR_PTR(-ENOMEM);
946 
947 	error = -ENOMEM;
948 	fattr = nfs_alloc_fattr();
949 	if (fattr == NULL)
950 		goto error;
951 
952 	/* Get a client representation */
953 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
954 	if (error < 0)
955 		goto error;
956 
957 	/* Probe the root fh to retrieve its FSID */
958 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
959 	if (error < 0)
960 		goto error;
961 	if (server->nfs_client->rpc_ops->version == 3) {
962 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
963 			server->namelen = NFS3_MAXNAMLEN;
964 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
965 			server->caps |= NFS_CAP_READDIRPLUS;
966 	} else {
967 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
968 			server->namelen = NFS2_MAXNAMLEN;
969 	}
970 
971 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
972 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh,
973 				fattr, NULL, NULL);
974 		if (error < 0) {
975 			dprintk("nfs_create_server: getattr error = %d\n", -error);
976 			goto error;
977 		}
978 	}
979 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
980 
981 	dprintk("Server FSID: %llx:%llx\n",
982 		(unsigned long long) server->fsid.major,
983 		(unsigned long long) server->fsid.minor);
984 
985 	nfs_server_insert_lists(server);
986 	server->mount_time = jiffies;
987 	nfs_free_fattr(fattr);
988 	return server;
989 
990 error:
991 	nfs_free_fattr(fattr);
992 	nfs_free_server(server);
993 	return ERR_PTR(error);
994 }
995 EXPORT_SYMBOL_GPL(nfs_create_server);
996 
997 /*
998  * Clone an NFS2, NFS3 or NFS4 server record
999  */
1000 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1001 				    struct nfs_fh *fh,
1002 				    struct nfs_fattr *fattr,
1003 				    rpc_authflavor_t flavor)
1004 {
1005 	struct nfs_server *server;
1006 	struct nfs_fattr *fattr_fsinfo;
1007 	int error;
1008 
1009 	server = nfs_alloc_server();
1010 	if (!server)
1011 		return ERR_PTR(-ENOMEM);
1012 
1013 	error = -ENOMEM;
1014 	fattr_fsinfo = nfs_alloc_fattr();
1015 	if (fattr_fsinfo == NULL)
1016 		goto out_free_server;
1017 
1018 	/* Copy data from the source */
1019 	server->nfs_client = source->nfs_client;
1020 	server->destroy = source->destroy;
1021 	refcount_inc(&server->nfs_client->cl_count);
1022 	nfs_server_copy_userdata(server, source);
1023 
1024 	server->fsid = fattr->fsid;
1025 
1026 	error = nfs_init_server_rpcclient(server,
1027 			source->client->cl_timeout,
1028 			flavor);
1029 	if (error < 0)
1030 		goto out_free_server;
1031 
1032 	/* probe the filesystem info for this server filesystem */
1033 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1034 	if (error < 0)
1035 		goto out_free_server;
1036 
1037 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1038 		server->namelen = NFS4_MAXNAMLEN;
1039 
1040 	error = nfs_start_lockd(server);
1041 	if (error < 0)
1042 		goto out_free_server;
1043 
1044 	nfs_server_insert_lists(server);
1045 	server->mount_time = jiffies;
1046 
1047 	nfs_free_fattr(fattr_fsinfo);
1048 	return server;
1049 
1050 out_free_server:
1051 	nfs_free_fattr(fattr_fsinfo);
1052 	nfs_free_server(server);
1053 	return ERR_PTR(error);
1054 }
1055 EXPORT_SYMBOL_GPL(nfs_clone_server);
1056 
1057 void nfs_clients_init(struct net *net)
1058 {
1059 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1060 
1061 	INIT_LIST_HEAD(&nn->nfs_client_list);
1062 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1063 #if IS_ENABLED(CONFIG_NFS_V4)
1064 	idr_init(&nn->cb_ident_idr);
1065 #endif
1066 	spin_lock_init(&nn->nfs_client_lock);
1067 	nn->boot_time = ktime_get_real();
1068 }
1069 
1070 #ifdef CONFIG_PROC_FS
1071 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1072 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1073 static void nfs_server_list_stop(struct seq_file *p, void *v);
1074 static int nfs_server_list_show(struct seq_file *m, void *v);
1075 
1076 static const struct seq_operations nfs_server_list_ops = {
1077 	.start	= nfs_server_list_start,
1078 	.next	= nfs_server_list_next,
1079 	.stop	= nfs_server_list_stop,
1080 	.show	= nfs_server_list_show,
1081 };
1082 
1083 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1084 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1085 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1086 static int nfs_volume_list_show(struct seq_file *m, void *v);
1087 
1088 static const struct seq_operations nfs_volume_list_ops = {
1089 	.start	= nfs_volume_list_start,
1090 	.next	= nfs_volume_list_next,
1091 	.stop	= nfs_volume_list_stop,
1092 	.show	= nfs_volume_list_show,
1093 };
1094 
1095 /*
1096  * set up the iterator to start reading from the server list and return the first item
1097  */
1098 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1099 				__acquires(&nn->nfs_client_lock)
1100 {
1101 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1102 
1103 	/* lock the list against modification */
1104 	spin_lock(&nn->nfs_client_lock);
1105 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1106 }
1107 
1108 /*
1109  * move to next server
1110  */
1111 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1112 {
1113 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1114 
1115 	return seq_list_next(v, &nn->nfs_client_list, pos);
1116 }
1117 
1118 /*
1119  * clean up after reading from the transports list
1120  */
1121 static void nfs_server_list_stop(struct seq_file *p, void *v)
1122 				__releases(&nn->nfs_client_lock)
1123 {
1124 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1125 
1126 	spin_unlock(&nn->nfs_client_lock);
1127 }
1128 
1129 /*
1130  * display a header line followed by a load of call lines
1131  */
1132 static int nfs_server_list_show(struct seq_file *m, void *v)
1133 {
1134 	struct nfs_client *clp;
1135 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1136 
1137 	/* display header on line 1 */
1138 	if (v == &nn->nfs_client_list) {
1139 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1140 		return 0;
1141 	}
1142 
1143 	/* display one transport per line on subsequent lines */
1144 	clp = list_entry(v, struct nfs_client, cl_share_link);
1145 
1146 	/* Check if the client is initialized */
1147 	if (clp->cl_cons_state != NFS_CS_READY)
1148 		return 0;
1149 
1150 	rcu_read_lock();
1151 	seq_printf(m, "v%u %s %s %3d %s\n",
1152 		   clp->rpc_ops->version,
1153 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1154 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1155 		   refcount_read(&clp->cl_count),
1156 		   clp->cl_hostname);
1157 	rcu_read_unlock();
1158 
1159 	return 0;
1160 }
1161 
1162 /*
1163  * set up the iterator to start reading from the volume list and return the first item
1164  */
1165 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1166 				__acquires(&nn->nfs_client_lock)
1167 {
1168 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1169 
1170 	/* lock the list against modification */
1171 	spin_lock(&nn->nfs_client_lock);
1172 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1173 }
1174 
1175 /*
1176  * move to next volume
1177  */
1178 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1179 {
1180 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1181 
1182 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1183 }
1184 
1185 /*
1186  * clean up after reading from the transports list
1187  */
1188 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1189 				__releases(&nn->nfs_client_lock)
1190 {
1191 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1192 
1193 	spin_unlock(&nn->nfs_client_lock);
1194 }
1195 
1196 /*
1197  * display a header line followed by a load of call lines
1198  */
1199 static int nfs_volume_list_show(struct seq_file *m, void *v)
1200 {
1201 	struct nfs_server *server;
1202 	struct nfs_client *clp;
1203 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1204 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1205 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1206 
1207 	/* display header on line 1 */
1208 	if (v == &nn->nfs_volume_list) {
1209 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1210 			    "                              FSC\n");
1211 		return 0;
1212 	}
1213 	/* display one transport per line on subsequent lines */
1214 	server = list_entry(v, struct nfs_server, master_link);
1215 	clp = server->nfs_client;
1216 
1217 	snprintf(dev, sizeof(dev), "%u:%u",
1218 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1219 
1220 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1221 		 (unsigned long long) server->fsid.major,
1222 		 (unsigned long long) server->fsid.minor);
1223 
1224 	rcu_read_lock();
1225 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1226 		   clp->rpc_ops->version,
1227 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1228 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1229 		   dev,
1230 		   fsid,
1231 		   nfs_server_fscache_state(server));
1232 	rcu_read_unlock();
1233 
1234 	return 0;
1235 }
1236 
1237 int nfs_fs_proc_net_init(struct net *net)
1238 {
1239 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1240 	struct proc_dir_entry *p;
1241 
1242 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1243 	if (!nn->proc_nfsfs)
1244 		goto error_0;
1245 
1246 	/* a file of servers with which we're dealing */
1247 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1248 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1249 	if (!p)
1250 		goto error_1;
1251 
1252 	/* a file of volumes that we have mounted */
1253 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1254 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1255 	if (!p)
1256 		goto error_1;
1257 	return 0;
1258 
1259 error_1:
1260 	remove_proc_subtree("nfsfs", net->proc_net);
1261 error_0:
1262 	return -ENOMEM;
1263 }
1264 
1265 void nfs_fs_proc_net_exit(struct net *net)
1266 {
1267 	remove_proc_subtree("nfsfs", net->proc_net);
1268 }
1269 
1270 /*
1271  * initialise the /proc/fs/nfsfs/ directory
1272  */
1273 int __init nfs_fs_proc_init(void)
1274 {
1275 	if (!proc_mkdir("fs/nfsfs", NULL))
1276 		goto error_0;
1277 
1278 	/* a file of servers with which we're dealing */
1279 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1280 		goto error_1;
1281 
1282 	/* a file of volumes that we have mounted */
1283 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1284 		goto error_1;
1285 
1286 	return 0;
1287 error_1:
1288 	remove_proc_subtree("fs/nfsfs", NULL);
1289 error_0:
1290 	return -ENOMEM;
1291 }
1292 
1293 /*
1294  * clean up the /proc/fs/nfsfs/ directory
1295  */
1296 void nfs_fs_proc_exit(void)
1297 {
1298 	remove_proc_subtree("fs/nfsfs", NULL);
1299 }
1300 
1301 #endif /* CONFIG_PROC_FS */
1302